Multi-omics investigation of Porphyromonas gingivalis exacerbating acute kidney injury through the gut-kidney axis

Periodontitis is closely related to renal health, but the specific influence of Porphyromonas gingivalis (P. gingivalis), a key pathogen in periodontitis, on the development of acute kidney injury (AKI) in mice has not been fully elucidated. In our study, AKI was induced in mice through ischemia-reperfusion injury while administering oral infection with P. gingivalis. Comprehensive analyses were conducted, including 16S rRNA sequencing, liquid chromatography-mass spectrometry (LC-MS) metabolomics, and transcriptome sequencing. In vitro, the identified metabolite was used to stimulate mouse neutrophils. Subsequently, these modified neutrophils were co-cultured with mouse renal tubular epithelial cells. The results showed that oral infection with P. gingivalis significantly exacerbated AKI in mice. 16S rRNA sequencing revealed notable shifts in gut microbiota composition. LC-MS metabolomics analysis identified significant metabolic alterations, particularly the upregulation of 3-indoleacrylic acid in the serum. Transcriptome sequencing showed an increased expression of neutrophilic granule protein (Ngp), which was closely associated with 3-indoleacrylic acid, and the presence of Porphyromonas. Cellular experiments demonstrated that 3-indoleacrylic acid could activate neutrophils, leading to an elevation in NGP protein levels, a response that was associated with renal epithelial cell injury. Oral infection with P. gingivalis exacerbated AKI through the gut-kidney axis, involving gut microbiota dysbiosis, metabolic disturbances, and increased renal expression of Ngp. This study provides novel insights into the relationship between periodontal health and renal function. Porphyromonas gingivalis oral infection disrupted the balance of gut microbiota and was an important modifier determining the severity of acute kidney injury. Under the "gut-kidney axis," P. gingivalis might cause an increase in the level of the gut microbial metabolite 3-indoleacrylic acid, interfering with kidney immunity and disrupting the maintenance of kidney epithelium.